A novel laser interference lithography system with enhanced tunablility in pattern periodicity and coverage has been
designed and tested for large-area nano-patterning in a wide range of a pattern frequency. The tunable feature has been
achieved by using two rotational mirrors on expanded beam paths at specific angles for a designed period. With a 325
nm laser wavelength, uniform resist nano-patterns of 250, 500, and 750 nm have been experimentally demonstrated on a
4-inch silicon substrate. This new interferometer configuration offers a convenient and robust way to prepare large-area
nanostructures with superior tunability in pattern periods.
Recent nanotechnology revolutions have cast increased challenges to biotechnology including bio-adhesion of cells.
Surface topography and chemistry tailored by the nanotechnology exert significant effects on such applications so that it
is necessary to understand how cells migrate and adhere on three-dimensional micro- and nanostructures. However, the
effects of the surface topography and chemistry on cell adhesions have not been studied systematically and interactively
yet mostly due to the inability to create well-controlled nanostructures over a relatively large surface area. In this paper,
we report on the bio-adhesions of varying cell types on well-ordered (post and grate patterns), dense-array (230 nm in
pattern periodicity), and sharp-tip (less than 10 nm in tip radius) nanostructures with varying three-dimensionalities (50-
500 nm in structural height). Significantly lower cell proliferation and smaller cell size were measured on tall
nanostructures. On a grate pattern, significant cell elongation and alignment along the grate pattern were observed. On
tall nanostructures, it was shown that cells were levitated by sharp tips and easily peeled off, suggesting that cell
adherence to the tall and sharp-tip nanostructures was relatively weak. The control of cell growth and adherence by the
nanoscale surface topographies can benefit the micro- and nanotechnogies-based materials, devices, and systems, such as
for anti-biofouling and anti-microbial surfaces. The obtained knowledge by this investigation will also be useful to deal
with engineering problems associated with the contact with biological substances such as biomaterials and biosensors.